The present invention relates to a cooling device for a vehicle mounted generator which is driven by an engine of the vehicle.
FIG. 1 shows schematically a conventional cooling device for a vehicle mounted generator, which is shown, for example, in Japanese Kokai No. 83557/1984.
In FIG. 1, reference numerals 1, 2, 3, 4, 5, 6 and 7 depict an engine mounted on a vehicle, a cylinder block constituting the engine, a water jacket provided around the cylinder block 2, an upper hose for guiding a coolant heated in the water jacket 3 to a radiator, the radiator, a lower hose for guiding the coolant cooled in the radiator 5 to the water jacket 3 and a water pump provided in between the lower hose 6 and the water jacket 3 for pressurizing the coolant to circulate it forcibly, respectively. An a.c. generator 8 driven by the engine has a bracket through which a portion of the coolant of the engine passes. The portion of the coolant flows through a coolant passage formed in the bracket to cool a stator core and a stator coil of the generator and then flows into the lower hose 6.
In a device constructed as above, a portion of the coolant for the engine 1 flows from the water jacket 3 provided around the cylinder block 2 into the coolant passage formed in the generator 8, and after it cools the stator core and the stator coil of the generator 8 flows into a discharge passage, i.e., the lower hose 6 extending from the radiator 5. The coolant flowing out from the lower hose 6 is subjected to a suction force due to the pump 7. Therefore, the circulation of the coolant flowing through the coolant passage in the generator 8 is maintained favorably, resulting in an effective cooling of the stator core and the stator coil.
In the conventional cooling device mentioned above, when the amount of coolant is reduced due to a breakage, etc. of the radiator 5, the cooling of the engine becomes insufficient, sufficient, so that the temperature of the engine increases abnormally and hence the temperature of the coolant increases abnormally. If the operator of the vehicle does not become aware of this fact, the high temperature coolant or a high temperature coolant gas may be supplied by the water pump 7 to the coolant passage in the generator 8. In such case, the stator core and the stator coil thereof may be cooled insufficiently or not at all and in the worst case they may be heated.
In winter season, the coolant in the coolant passage of the generator 8, even if the amount thereof is reduced, tends to cool the components excessively.